Similarities: Both are investment programs that target for your retirement.

Differences: The traditional IRA is taxable when withdraw, and it is deductible on tax return.

However, Roth IRA is nontaxable when withdraw, and it is not deductible on tax return.

When to withdraw: In normal situation, the money should be withdrawn when retired. Technically, you can withdraw the money anytime during your lifetime, but you have to pay a penalty for early withdrawal.

Tax implication: When you withdraw money from traditional IRA, it is taxable. On the other hand, it is nontaxable to withdraw money from a Roth IRA.

Why traditional over Roth - Choosing traditional IRA can lower your current tax because it is pre-tax money. the amount you will be taxed would be lower than that in Roth IRA, which takes out money after taxation.